Method of Managing Group of Dynamic Multicast Efficiently

1. A method of efficiently dividing dynamic multicast groups, comprising: a first step of a second management server requesting a first management server to divide a group of the first management server; a second step of the first management server transmitting a list of group members to the second management server; a third step of, when the second management server requests one or more members whose group needs to be changed to join a group of the second management server because of the division of the group, the members approving the joining of the second management server and the second management server starting a multicast service; a fourth step of the second management server notifying a last server and the first management server that the members have been changed; a fifth step of the first management server deleting, from its group, the members whose group has been changed and requesting the members to secede from its group; a sixth step of the members approving the secession from the group of the first management server and transmitting acknowledge data, corresponding to the secession from the group of the first management server, to the first management server; and a seventh step of the last server transmitting contents of the change of the group, received in the fourth step, to the first management server and the second management server.

2. The method as claimed in claim 1 , wherein the last server manages members of the first management server and the second management server.

3. The method as claimed in claim 1 , wherein: the first management server, the second management server, and the last server exchange state information therebetween through communication, and the multicast service is synchronized.

4. The method as claimed in claim 1 , wherein the division of the group requested in the first step is performed when M/K is exceed, wherein the M is a maximum number of members which are managed by the first or second management server and the K is a number of members which are managed by the first or second management server.

5. The method as claimed in claim 1 , wherein the group joining process of the third step comprises: a first process of the members receiving a group key and a session key from the last server in order to receive the multicast service; a second process of the second management server authenticating the members using the group key and the session key; and a third process of the second management server transmitting a group IP to the members.

6. The method as claimed in claim 1 , further comprising the step of, when the members secede from the group in the sixth step, the first management server requesting a group key update from the last server and receiving an updated group key from the last server in response to the request.

7. A method of efficiently merging dynamic multicast groups, comprising: a first step of a second management server requesting a first management server to merge a group of the second management server with a group of the first management server; a second step of the first management server requesting a list of group members from the second management server and receiving the list of the group members from the second management server; a third step of the first management server waiting for a multicast service, and transmitting a group address to the group members and, at the same time, requesting the group members to join the group of the first management server; a fourth step of the group members approving the joining of the first management server and the first management server starting the multicast service; a fifth step of the second management server requesting a last server to delete the group of the second management server and the first management server providing the last server with contents of a change in the group members resulting from the mergence; and a sixth step of the last server transmitting acknowledge data for the contents of the change in the group members to the first management server and deleting the group of the second management server.

8. The method as claimed in claim 7 , wherein the mergence of the group requested in the first step is performed when a use rate of a group is smaller than S/M*100, wherein the S is a number of members which are being provided with service by the first or second management server and the M is a maximum number of members which are managed by the first or second management server.

9. The method as claimed in claim 7 , wherein the group joining process of the fourth step comprises: a first process of the members receiving a group key and a session key from the last server in order to receive the multicast service; a second process of the second management server authenticating the members using the group key and the session key; and a third process of the second management server transmitting a group IP to the members.

10. The method as claimed in claim 7 , further comprising the step of, when, in the sixth step, there is a change in the members because of the mergence of the group of the second management server with the group of the first management server, the first management server requesting a group key update from the last server and receiving an updated group key from the last server in response to the request.

11. The method as claimed in claim 7 , wherein: the first management server, the second management server, and the last server exchange state information therebetween through communication, and the multicast service is synchronized.